Method for making a double row roller bearing retainer

ABSTRACT

A single retainer retains two sets of circumferentially separated rollers. The retainer is made from flat metal stock. A method for making a double row retainer bearing from strip stock is disclosed.

This is a division of application Ser. No. 764,680 filed July 12, 1985,now U.S. Pat. No. 4,605,322 issued Aug. 12, 1986, which is acontinuation of application Ser. No. 556,559 filed Nov. 11, 1983, nowabandoned.

This invention relates to double row roller bearings. More particularlythis invention is one piece double row roller bearing retainer made fromflat metal stock.

Currently available double row roller bearings, which have a metalretainer assembly, require two separate retainers to retain and guidethe rollers in the double row roller bearing. A separate metal retaineris required for each set of rollers. An example is the roller retainerfor roller bearings shown in U.S. Pat. No. 2,805,108 granted to N. A.Palmgren on Sept. 3, 1957 and entitled "Roller Cages for RollerBearing".

This invention is a double row roller bearing retainer which is made ofmetal but is made in a single piece to retain both sets of rollers inthe retainer.

Briefly described, the new double row roller bearing retainer is madefrom flat metal stock. The retainer includes a pair of axially separatedend rings interconnected by circumferentially separated axiallyextending cross-bars, and an axially centered ring. The axially centeredring may be an integral center ring or a separate metal band which hasbeen attached to the cross-bars by methods such as welding.

Briefly described, the new method of making a double row roller bearingretainer from flat metal stock comprises the steps of making a pluralityof pockets in a flat metal strip. If the completed bearing is to have anintegral center ring, the dimensions of the pockets are such that anintegral center bar is formed. The cross-bars formed by the making ofthe plurality of pockets is shaped for roller guidance and rollerretention. The flat metal strip is then U-formed, that is, the edges ofthe strip are bent to provide a strip having a U-shaped cross-section.Thereafter, a predetermined length of the U-formed strip is cut off andwrapped into an annular retainer. The circumferential terminals of theend ring are then bonded together to form a complete retainer if theintegral center bar was formed by the pockets. If not, a separateaxially centered metal band is connected to the cross-bars.

The invention as well as its many advantages may be further understoodby reference to the following detailed description and drawings inwhich:

FIG. 1 shows in cross section one-half of a preferred embodiment of theinvention;

FIG. 2 shows in cross section one-half of a second preferred embodimentof the invention;

FIG. 3 is a top fragmentary view of a flat metal strip before it isU-formed and wrapped into a third preferred embodiment of the invention.

FIG. 4 is a top fragmentary view of the metal strip of FIG. 3 after ithas been U-formed, wrapped, and welded;

FIG. 5 is a top fragmentary view of a flat metal strip condition beforeU-forming and wrapping of still another preferred embodiment of theinvention;

FIG. 6 is a top fragmentary view of the metal strip of FIG. 5 after ithas been U-formed, wrapped into an annular retainer, and welded;

FIG. 7 shows in cross-section one-half of another preferred embodimentof the invention utilizing a separate band which has been welded to thecross-bars of the retainer;

FIG. 8 is an enlarged top fragmentary view or the retainer of FIG. 7;

FIG. 9 illustrates one of the steps used to make a still furtherpreferred embodiment from the flat strip metal material;

FIG. 10 is useful to illustrate a subsequent step;

FIG. 11 is a view similar to FIG. 9 and FIG. 10 illustrating asubsequent step;

FIG. 12 is a view taken along lines 12--12 of FIG. 11 and in thedirection of the arrows;

FIG. 13 shows the final step of wrapping the U-formed metal strip intoan annular member and welding a separate band to the annular ember;

FIG. 14 is an enlarged fragmentary view of a bearing utilizing theretainer of FIG. 13;

FIG. 15 is a sectional view taking along lines 15--15 of FIG. 14 in thedirection of the arrows with the races and rollers removed;

FIG. 16 is a view taken along lines 16--16 of FIG. 15 and in thedirection of the arrows; and

FIG. 17 is a view taken along lines 17--17 of FIG. 15 and in thedirection of the arrows; and

FIG. 18 is a view showing the inner race turned 90 degrees out of phasewith the retainer of FIG. 13 through FIG. 17 for assembly.

In the various figures, like parts are referred to by like numbers.

Referring to the drawings and more particularly to FIG. 1, thisemobdiment includes an annular inner race 10 and an annular outer race12. An inner curved surface 14 is formed on the inside of annular outerrace 12. The inner race 10 has curved raceways 16 and 18 extendingangularly toward the bearing axis and separated by annular protrusion44. The spherical rollers 20 and 22 contact the raceways 16 and 18,respectively, and also contact the outer race surface 14. The axes ofthe rollers 20 and 22 are at an angle to the spherical roller bearingaxis.

The retainer includes a pair of axially separated end rings 24 and 26interconnected by a plurality of circumferentially separated axiallyextending cross-bars 30 (one cross-bar is shown in FIG. 1). An axiallycentered ring 32 forms an integral part of the retainer. A first set ofcircumferentially separated pockets 28 are formed by end ring 24,cross-bars 30, and the integral axially centered ring 32. A second setof circumferentially separated pockets 31 are formed by end ring 26,cross-bars 30, and the axially centered ring 32.

The cross-bars are generally U-shaped in cross-section and include thelegs 36 and 38 extending radially outwardly from end rings 24 and 26,respectively, with the curved portion interconnecting the legs. TheU-shaped cross-section provides pockets 28 and 31 each of which extendaxially towards the end rings 24 and 26 of the retainer and radiallyinward. End rings 24 and 26 are piloted on annular flanges 40 and 42,respectively, of the inner race 10.

For assembly purposes, if the end rings 24 and 26 each have the sameinside diameter throughout their entire circumference, the innerdiameter of the end rings 24 and 26 must be equal to or greater than theouter diameter of the axially centered annular protrusion 44. Thepiloting of the end rings 24 and 26 is provided by the flanges 40 and42, respectively, on the inner race 10.

In the embodiment of FIG. 2, the inner race 45 does not have any endflanges. To provide for the piloting of the end rings 24 and 26,non-metallic annuler rings 46 and 48 are inserted over the end rings 24and 26, respectively. The non-metallic members 46 and 48 may bemachined, molded, or made by the extrusion process and inserted by a"snap-fit" into the small diameters of the end rings 24 and 26.

The retainers shown in FIG. 1 and FIG. 2 are made from a flat metalstrip. The retainers are made by piercing or otherwise making aplurality of pockets in the flat metal strip. The cross-bars thus formedare shaped for roller guidance and for roller retension. The flat metalstrip is then U-formed to provide a strip having a U-shapedcross-section. A pre-determined length of the U-formed strip is then cutoff, wrapped, and the end rings welded, or otherwise bonded togetherinto the annular retainer shown in FIG. 1 or the annular retainer shownin FIG. 2. As the shaped flat piece is wrapped into an annular shape thecenter bar 32 is stretched and the end rings 24 and 26 are compressed.For certain size retainers, the required stretching of the center barand the compression of the end rings may be such that it would bedifficult to form the part from a flat metal material. One way ofsolving this problem is to make the embodiment of FIG. 3 and FIG. 4.

Referring to FIG. 3, which is a top fragmentary view of a flat metalstrip which has been pierced to form the pockets, the center bar 32remains an integral part of the retainer but is sheared through to formthe tongue and groove connection in which the tongue 50 at onecircumferential terminal of the bar 32 engages a groove 52 formed in theother circumferential terminal of the bar 32. The tongue and grooveconnection allows the bar 32 to move freely in a circumferentialdirection as the retainer diameter is formed. As shown in FIG. 4, oncethe retainer diameter is formed and the end rims 54 and 56 are formedinto the end rings 24 and 26, the tongue 50 is resistance welded ingroove 50 to make the center bar 32 one rigid member and to prevent thesheared portion from becoming distorted in application.

In the embodiment shown in FIG. 5 and FIG. 6, FIG. 5 is a fragmentaryview of a flat strip before forming. The fingers 55 and 57 are formed byshearing the center bar 32. Each finger extends along a side of theother finger with finger 55 contacting surface 59 and finger 57contacting surface 61. FIG. 6 shows the embodiment of FIG. 5 after theretainer diameter has been formed and the rims 54 and 56 turned inwardlyto form end rings 24 and 26, respectively. Each finger 55 and 57 extendspartially along the side of the other finger and are resistance weldedto form a rigid central bar 32.

In the preferred embodiment of FIG. 7 and FIG. 8, the cross-bars 60extend axially from one end ring 24 to the other end ring 26. In thisembodiment, the center bar is not an integral part of the retainer; itis a separate metal band 62 which is connected to the cross-bars 60 bywelding or other suitable bonding methods. The separate metal band 62has a plurality of circumferentially separated radially inwardlyextending projections 58. The projections 58 extend between the rollers20 and 22 and reach in between the rollers 20 and 22 and serve to pilotthe retainer on the protrusion 44 of the inner race 10. Note that thebottom of the projection 58 reaches the protrusion 44 of the inner race10.

FIGS. 14 through 18, inclusive, show still another preferred embodimentof the invention. Referring to FIG. 14 the retainer is located in theannulus separating the inner race 63 from the outer race 64. Theretainer has pockets for guiding and retaining a first set of rollers65. A second set of rollers (not shown) is located in the pocketsaligned with the pockets guiding and retaining rollers 65.

As shown more clearly in FIGS. 15 through 17, the retainer includes apair of axially separated end rings 66 and 68. Each cross-bar 70 extendsfrom one end ring 66 to the other end ring 68. A separate metal band 72is axially centered on the cross-bars 70. End ring 66 has alternatestraight portions 74 and scallops 76 (see FIG. 14). End ring 68 has thesame shape as end ring 66.

The inner race 63 has a cross-section (see FIG. 18) like thecross-section of the inner race 45 of FIG. 2 including the protrusion44. The protrusion of inner race 63 has a larger outside diameter thanthe inside diameter of end rings 66 and 68. However, the rounded peaksof the scallops 76 have a larger diameter than the outside diameter ofthe inner race protrusion 44. Thus even though the inside diameter ofthe portions 74 of the retainers is less than the outside diameter ofthe protrusion of the inner race, the inner race may be inserted intothe retainers simply by placing the inner race 63 with its axesperpendicular to the axis of the retainer, aligning the protrusion withtwo diametrically opposite scallops 76, pressing the inner race throughsaid scallops into the retainer, and turning the inner race so the axisis the same as the axis of the retainer.

Looking at FIG. 15 it can be seen that the cross-bars 70 are each of agenerally U-shape with the legs 80 and 82 extending radially outwardlyfrom the straight portions 74 of end rings 66 and 68. Radially offsetportions 84 and 86 are provided on the cross-bars 70 at points axiallycentered between the end ring 68 and the band 72, and the end ring 66and the band 72, respectively. Referring to FIG. 16, circumferentiallyextending projections 88 and 90 extend from the offset portion 84.Circumferentially extending projections 92 and 94 extend from offsetportion 86. Referring to FIG. 17, the sides 96, 98, 100, and 102 ofprojections 88, 90, 92, and 94, respectively, all taper radiallyinwardly. The rollers are guided circumferentially by those areasadjacent each side of the protrusions 88, 90, 92, and 94. The rollersare retained against falling radially outwardly by the tapered surfaces96, 98, 100, and 102. The rollers are kept in place axially by the endrings 66 and 68 and the band 72. Coined depressions 104, 105, and coineddepressions 106, 107 are provided near each end of each cross-bar. Thuswhen U-forming the retainer, as the flat metal stock is formed into theU-shape, the tension on the outside part of the cross-bar as it is beingbent and the compression on the inside part of the cross-bar as it isbeing bent are minimized.

The method of making the double row roller bearing retainer of FIGS. 14through 17, inclusive, is illustrated in FIGS. 9 through 13, inclusive.Referring to FIG. 9, the flat metal stock 110 has been pierced to formthe pockets in the flat metal strip. The metal strip 110 also has hadthe scallops 76 formed on its side edges. Thereafter as shown in FIG.10, the roller retaining projections 88, 90, 92 and 94 are formed on themetal strip.

In FIG. 11 and FIG. 12, the metal strip 110 has been U-formed. As can bebeen by looking at FIG. 12, the cross-bars have been shaped to providethe radially offset portions 84 and 86 and the tapered portions such as96 and 100 shown in FIG. 12.

The final steps are the wrapping of the U-formed member into an annularshape as shown in FIG. 13 and welding or otherwise satisfactorilyattaching the band 72 to the circumferentially separated cross-bars.

The axially centrally located separate bands, such as band 72, may beplaced on the outside of the cross-bars or on the inside of thecross-bars or both. Also for added strength, the band may haveoverlapping sections.

The invention has been described and illustrated as a retainer, that is,the rollers retained against outside removal. However, the inventionalso includes cages, that is, the rollers are retained against bothoutside and inside removal, and separators, that is, the rollers arseparated but will fall out if the separator is removed from thebearing.

We claim:
 1. A method of making a double row roller bearing retainerfrom flat metal stock comprising the steps of:making a plurality ofpockets in a flat metal strip to provide pockets in the flat metal stripseparated by cross-bars, and at the same time making scallops on eachedge of the flat metal strip; shaping the cross-bars for roller guidanceand for roller retention; U-forming the flat metal strip to provide astrip having a U-shaped cross-section; cutting off a predeterminedlength of the U-formed strip to provide a U-formed strip having twoends; wrapping the predetermined length into an annular retainer; andbonding the two ends together.
 2. The method of claim 1 wherein: anaxially centered band is wrapped around the retainer and bonded to thecross-bars.
 3. The method of claim 1 wherein: the dimensions of thepockets made are such that a transversely centered integral bar isformed.